실험적 급성 허혈성 신부전에서 Verapamil 이 혈중 Polyamine 동태에 미치는 영향

원동준(Dong Jun Won),권현민(Hyun Min Kwon),김용섭(Yong Seop Kim),구자룡(Ja Ryong Gu),권영주(Young Ju Kwon),조원용(Won Yong Cho),김형규(Hyung Kyu Kim) 대한내과학회 1991 대한내과학회지 Vol.40 No.6

N/A It has been proposd that calcium entry from an external medium increases intracellular free calcium to toxic levels during ischemic acute renal failure, and verapamil (ARF) has been suggested as the agentblocking calicium entry into renal cells and protecting renal function during ischemic injury. Polyamines, anorganic cations that play various roles in normal cellular proliferation and differentiation, accumulate in renal failare. Alsa it has been suggested tht the synthesis and metabolism of polyamine are influence by acute changes of the general condition, such as acute renal failure, and are mediated by a calcium influx into the cells. The study was designed to study the protective effects of systemic verapamil pretreatment on renal function and the influence on polyamine metabolism in experimental ischemic ARF in cats. For these purpose, the experimental animals were divided into 2 groups. While Group I (n=5) was an ischemic ARF model by renal artery clamping for 60 minutes, Group II (n=5) was ischemic ARF with systemic verapamil (5 ml/min/kg) pretreatment. The creatinine clearance and plasma and urinary polyamine were measured in each group before and after the renal artery clamp. The results were as follows: 1) Creatinine clearance before and after the renal artery clamp were 10.64±7.18 ml/min/kg and 2.09±1. 70 ml/min/kg in Group I, 4.47±3.38 ml min/kg and 0.60±0.79ml/min/kg in Group II, respectively, So creatinine clearance decreased more significantly in Group II campared with Group I. 2) Plasma polyamine increased after ischemia in Group I. In group I, plasma levels of putrescine, spermidine, and spermine before ischemia were 4.75±0.40 nmol/ml, 0.69±0.09 nmol/ml, and 0.83±0.63 nmol/ml, were elevated to 7.17±2.91 nmol/ml, 9.83±1.46 nmol/ ml, and 2.64±1.14nmol/ml after ischemia. But in Group II, the plasma level of polyamine was not changed, and especially, spermine decreased significantly from 0.83±0.27 before ischemia to 0.49±0.23 nmol/ml after ischenmine (p=0.033). 3) Urine polyamine excretion decreased after ischemia in Group I and Group II. In Group II, urinary excretion of spermidine and spermine before ischemia, 0.13±0.10 nmol/min and 0.17±0.13nmol/min, decreased after ischemia to 0.01±0.01nmol/min (p=0.019) and 0.032±0.26 nmol/min (p=0.0257). 4) In renal tissue, spermine content vas highest. In Group II, preischemic spermine were 397.20 nmol/g and increased to 646.66nmol/g after ischema, But there were no significant changes in the polyamine contents in Group II. From these data, it was suggested that systemic verapamil pretreatment exerts no protective effect on ischemic ARF. Plasma polyamines are elevated in ischemic ARF, and verapamil may protect these elevations.

간헐식 흐름방식을 활용한 수직 · 수평 습지의 정화효율 평가

주광진(Kwang Jin Joo),이동민(Dong Min Lee),김기중(Ki Jung Kim),조용철(Yong Chul Cho),장광현(Gwang Hyeon Jang),최이송(I Song Choi),오종민(Jong Min Oh) 응용생태공학회 2017 Ecology and resilient infrastructure Vol.4 No.3

본 연구에서는 부영양화의 원인이 되는 질소와 인의 제거 효율을 향상시킬 목적으로 광물질을 활용한 여재를 이용하여 호기, 혐기의 흐름조건을 만들어주기 위한 수직·수평 흐름 인공습지를 고안하여 아크릴 반응조로 제작한 후 성능평가를 진행하였다. 수직·수평 흐름형 인공습지의 경우 호기 및 혐기조건을 평가하기 위해서 반응조 내 용존산소(DO) 농도를 측정해본 결과 호기상태에서는 2.7 ㎎/L, 혐기상태에서는 N.D로 확인되어 목적에 부합된 결과가 확인되었다. 실험결과에서는 SS 저감효과가 140 min, 80 min, 60 min의 운전시간에서 각각 94%, 91%, 61%의 효율을 보였고, T-P의 경우 각각의 운전시간에 따라 84%, 71%, 63%의 저감효율을 보였다. 또한 T-N의 경우 각각의 운전시간에 따라 63%, 49%, 42%의 저감효율을 보여 기존의 습지가 12~24 hr 체류시간을 가지는 것에 비하여 짧은 운전시간에도 높은 처리효율을 보이는 것으로 확인되었다. 본 연구에서는 수직·수평 흐름 방식을 복합 적용하여 기존 인공습지의 단점을 보완하기 위해 기술개발을 진행한 것으로 어떠한 기능적 효과를 갖는지 확인하였고, 향후 이에 대한 현장적용을 위한 운영 및 관리적 차원의 메커니즘 연구가 추가로 진행 될 필요가 있다. Nitrogen and phosphorus are key factors in causing eutrophication of water body. In this study, ceramics media was selected to increase the removal efficiency of nitrogen and phosphorus. We designed vertical, horizontal flow constructed wetlands to create aerobic and anaerobic flow conditions by using the media, then proceeded to performance evaluations after acrylic reactors were produced. In the case of vertical and horizontal flow constructed wetlands, we measured oxygen concentrations to evaluate aerobic and anaerobic conditions. we got the result of 2.7 ㎎/L in the aerobic condition, N.D in the anaerobic condition respectively, which suited our purpose. The result of the combined vertical and horizontal flow condition showed that the removal efficiency of SS was 94%, 91%, 61% at 140 min, 80 min, 60 min of running times, respectively, and the removal efficiency of T-P was 84%, 71%, 63% during each running time. In case of T-N, the removal efficiency was 63%, 49%, 42% during each running time. We found that the reactor exerted better removal efficiency when in the short time compared to 12 - 24 hr residence time of existing wetlands. In this study, we conducted experiments to explore functional effects after applying combined vertical and horizontal flow methods in the field. Further study will be carried out to identify its mechanism and administrative perspective.

Genome-wide investigation of a Korean synthetic breed, Woori-Heukdon using the Illumina PorcineSNP60K BeadChip

Yong‑Min Kim,Ha‑Seung Seong,Jung‑Jae Lee,Da‑Hye Son,Jin‑Su Kim,Soo‑Jin Sa,Young‑Sin Kim,Tae‑Jeong Choi,Kyu‑Ho Cho,Joon‑Ki Hong,Jung‑Woo Choi,Eun‑Seok Cho 한국유전학회 2020 Genes & Genomics Vol.42 No.12

Background: Woori-Heukdon (KWH) is a Korean synthetic pig breed generated using Chookjin-Duroc (KCD), Chookjin-Chamdon (KCC), and their crossbreds. Currently, there is a severe lack of studies investigating the Korean breed populations including wild boars (KWB) throughout the genome. Objective: This study was performed to investigate the genetic characteristics of Korean pig populations at the genome-wide level. Methods: Using the SNP dataset derived from genotyped and downloaded datasets using the Illumina PorcineSNP60K BeadChip, we compared the genomes of 532 individuals derived from 23 pig breeds to assess the genetic diversity, inbreeding coefficient, genetic differentiation, and population structure. Results: KWB showed the lowest average expected heterozygosity (HE = 0.1904), while KWH showed the highest genetic diversity (HE = 0.02859) among Korean populations. We verified that the genetic composition of KWH, showing USD of 74.8% and KCC of 25.2% in ADMIXTURE analysis. In population structure analyses, KCC was consistently shown to be separated from other pig populations. In addition, we observed gene flow from Western pigs to a part of Chinese populations. Conclusion: This study showed that Korean native pigs, KCC have genetic differences in comparison with Chinese and Western pigs; despite some historical records and recent genetic studies, we could not find any clear evidence that KCC was significantly influenced by Chinese or Western breeds in this study. We also verified the theoretical genomic composition of KWH at the molecular level in structure analyses. To our knowledge, this is the first genomic study to investigate the genomic characteristics of KWH and KCC.

노인환자에서 척추마취시 Benzodiazepine 계 약물의 효과

조남수,김용일,유병식,정종달,임경준,김민출 대한마취과학회 1993 Korean Journal of Anesthesiology Vol.26 No.2

Midazolam, a water soluble benzodiazepine, was compared with diazepam as the changes of eardiopulmonary function during sedation under the spinal anesthesia in elderly patients. The results were as follows; 1) Cardiovascular effect. At the conclusion after diazepam 0.05 mg/kg(Group D) or midazolam 0.02 mg/kg(Group M) injection, systolic, diastolic pressure and heart rate were significantly decreased(P$lt;0.05) in the both group from 3 min to 30 min, but maintained within normal range. However, it is not significant difference that each group. 2) Respiratory effect. SaO decreased significantly at 3 min. in M-group after midazolam injection but there was not significant difference from change in D-group. Respiratory rate, pH and PaCO₂ were not significantly changed between D-group and M-group. However, PaO₂ was significantly decreased(p$lt;0.05) within normal range at 3 min. in M-group after midazolam IV and significant difference between both groups. From the above results, We have concluded that IV administrationf small dose of diazepam or midaaolam during spinal anesthesia had a little changed in cardiopulmonary function. However, sedative effect was efficient.

응급실에서 기관내 삽관후 발생한 후두육아종 1례

조남수,김용배,조수형,송민엽,송성용 大韓應急醫學會 1996 대한응급의학회지 Vol.7 No.1

Endotracheal intubation has been used widely for the maintenance of airway in the emergency patient and CPR in the acute airway obstruction patient and to treat respiratory insufficiency. Endotracheal intubation has many advantages but it may cause several complications which rate about 4% of endotracheal intubation patient. Among these complications, laryngeal granuloma is a relatively rare complication arising about 1 case per 10,000∼20,000 cases. Authors report a case of laryngeal granuloma which developed after endotracheal intubation required during emergency treatment. Case: A 55-year old female patient visited Chosun University Hospital Emergency Room complaining of dyspnea, cyanosis and sweating on Feb. 8th 1995. According to past history, she had a little obesity, dyspnea on exercise and mild hypertension. At arrival, blood pressure was 240/110mmHg, pulse rate 150 rates/min, respiratory rate 12/min, body temperature 36.5℃ and cyanosis with sweating on whole body was observed. And the mental state was semicoma. At 5 minutes after arrival, sudden respiratory arrest developed and immediate endotracheal intubation which emergency treatment was performed it was difficult to intubate endotracheally due to short neck and obesity. At 1 hour after arrival, general condition of the patient recovered well and extubation was done. The patient was transferred to internal medicine department and discharged after 12 days of medical treatment. At 2 months after discharge, the patient felt a progressive hoarseness and foreign body sensation of larynx. She was diagnosed as laryngeal granuloma at ENT department of Chosun University. She underwent the surgical operation and discharged in good health after 7 days of admission.

Factors Influencing the Acrylamide Content of Fried Potato Products

Jin, Yong-Ik,Park, Kyeong-Hun,Chang, Dong-Chil,Cho, Ji-Hong,Cho, Kwang-Su,Im, Ju-Sung,Hong, Su-Young,Kim, Su-Jeong,Nam, Jung-Hwan,Sohn, Hwang-Bae,Yu, Hong-Seob,Chung, Ill-Min The Korean Society of Environmental Agriculture 2016 한국환경농학회지 Vol.35 No.4

BACKGROUND: Acrylamide (CAS No. 79-06-1) is known to be a carcinogenic compound, and is classified as a Group 2A compound by the International Agency for Research on Cancer (IARC, 1994). Acrylamide can be generated during the browning process via the non-enzymatic Maillard reaction of carbohydrates such as reducing sugars and of amino acids such as asparagine, both of which occur at a temperature above $120^{\circ}C$. Potato tubers contain reducing sugars, and thus, this will affect the safety of processed potato products such as potato chips and French fries. In order to reduce the level of acrylamide in potato processed products, it is therefore necessary to understand factors that affect the reducing sugar content of potatoes, such as environmental factors and potato storage conditions, as well as understanding factors affecting acrylamide formation during potato processing itself. METHODS AND RESULTS: Potatoes were cultivated in eight regions of Korea; For each of these different environments, soil physico-chemical characteristics such as pH, electrical conductivity, total nitrogen, available phosphate, and exchangeable cation content were measured and correlations with potato reducing sugar content and potato chip acrylamide levels were examined. The reducing sugar content in potato during storage for three months was determined and acrylamide level in potato chip was analyzed after processing. The storage temperature levels were $4^{\circ}C$, $8^{\circ}C$, or $10^{\circ}C$, respectively. The acrylamide content of chips prepared from potatoes stored at $10^{\circ}C$ or $20^{\circ}C$ for one month was analyzed and the different frying times were 2, 3, 5, and 7 min. CONCLUSION: This study showed that monitoring and controlling the phosphate content within a potato field should be sufficient to avoid producing brown or black potato chips. For potatoes stored at low temperatures, a reconditioning period ($20^{\circ}C$ for 20 days) is required in order to reduce the levels of reducing sugars in the potato and subsequently reduce the acrylamide and improve chip coloration and appearance.

반응표면분석법을 이용한 배 퓌레 열수처리 조건 최적화

박민경(Min Kyeong Park),조용식(Yong Sik Cho),장현욱(Hyun Wook Jang) 한국식품영양과학회 2022 한국식품영양과학회지 Vol.51 No.11

본 연구는 열수처리 온도(50, 70, 90°C) 및 열수처리 시간(15, 30, 45분)을 달리하여 배 퓌레를 제조한 후 품질특성을 분석하여 반응표면분석법을 통해 최적의 열수처리 조건을 구하고자 하였고, 중심합성계획법에 따라 총 9가지의 실험점에서 진행하였다. 열수처리 온도 및 시간을 독립변수로 정하고, 품질특성에 관련된 적색도, ΔE값, 일반세균, 대장균군, polyphenol oxidase 활성, 총 폴리페놀 함량, 총 플라보노이드 함량을 종속변수로 설정하였다. 독립변수가 종속변수에 미치는 영향에 대해 분석한 결과, 적색도와 갈변을 나타내는 ΔE값은 각각 -0.38~1.20, 0.97~11.88의 범위로 측정되었고, 반응식의 R2은 각각 0.9754, 0.9818이었다. 일반세균 및 대장균군의 생균수는 각각 0.00~4.91 log CFU/mL, 0.00~4.03 log CFU/mL의 범위였고, 반응식의 R²은 0.9849, 0.9714였다. 갈변의 원인이 되는 polyphenol oxidase 활성은 122.57~235.13 unit 범위였으며, 반응식의 R²은 0.8616의 값을 보였다. 배 퓌레의 유효성분으로 총 폴리페놀 함량 및 총 플라보노이드 함량은 각각 19.33~24.54 GAE mg/100 g, 4.56~5.78 GAE mg/100 g 범위였으며, 이때 반응식의 R²은 각각 0.9181, 0.9097을 나타내었다. 이를 바탕으로 contour map을 superimposing 하여 최적 열수처리 조건을 설정한 결과, 최적화된 열수처리 조건의 온도범위는 69.3~80.4°C, 시간 범위는 16.8~25.8분으로 나타났으며, 최적점은 74.6°C, 20.7분으로 나타났다. 이에 대해 모델의 신뢰성을 검증하기 위해 예측값과 실험값을 비교한 결과, 각 반응변수의 실험값은 모두 예측값의 95% 신뢰구간 및 예측구간 범위에 들어와 모델의 적합성을 확인하였다. This study analyzed the quality characteristics of pear puree by varying the hydrothermal treatment temperature (50, 70, and 90°C) and time (15, 30, and 45 min) and sought to determine the optimal hydrothermal treatment conditions through the response surface methodology. A total of nine experimental points were studied according to the central composite design. The temperature and time were set as independent variables, and the redness, ΔE value, aerobic bacteria, coliform group, polyphenol oxidase (PPO) activity, total polyphenol content (TPC), and total flavonoid content (TFC) related to the quality characteristics were set as dependent variables. The redness and the ΔE value were measured as −0.38∼1.20 and 0.97∼11.88, respectively, and the R² value was 0.9754 and 0.9818, respectively. The R2 value of viable cell counts were 0.9849 and 0.9714 in the aerobic bacteria and coliform groups. The PPO activity was 122.57∼235.13 g/min, and the R² value was 0.8616. The TPC and TFC as active ingredients of pear puree were in the range of 19.33∼24.54 and 4.56∼5.78 GAE mg/100 g, respectively, and the R² values were 0.9181 and 0.9097, respectively. Based on this, the contour map was superimposed to set the optimal hydrothermal treatment conditions. The optimum points derived were 74.6°C and 20.7 min. When the predicted and the experimental values were compared to verify the reliability of the model, all the experimental values of each of the response variables were within the 95% confidence and prediction intervals, confirming the suitability of the model.

위암환자의 복강내에 투여한 Mitomycin C-Carbon Particle의 Mitomycin 용출에 관한 연구

노승무,조영훈,정경수,오정연,김진향,양준묵,강대영,송규상,조준식,최선웅,이진호,민병무,김용백,김창식,박근성,인현빈,정현용,김학용 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

Locoregional recurrence is the most common type of recurrence in surgical operation of gastric adenocarcinoma, and peritoneal dissemination is one of the most difficult problems in advanced gastric adenocarcinoma treatment. Because the peritoneal cavity is the most common site of the first recurrence after gastric cancer resection, intraperitoneal chemotherpy seems a logical choice for cancer chemotherapy. The Mitomycin C(MMC) adsorbed by the activated charcoal particles(CH) is relatively released when the drug concentration surrounding the carbon particles becomes low in the peritoneum of the peritoneal cavity. For the intraperitoneal chemotherapy on the advanced gastric adenocarcnoma, mitomycin C adsorbed on activated carbon particles was administered in the peritoneal cavity just before abdominal wall closure. The closed drainage tubes were inserted in the peritoneal cavity and clamped for tuo hours after completion of operation. MMC concentrations were serially measured in peritoneal fluid, plasma and urine at 2hour, 48 hour, 72 hour and 168 hour following its administration in order to study the efficacy of the MMC-CH as a drug delivery system. There were minimal toxicities in born marrow, liver, and gastrointestinal system after intraperitoneal MMC-CH administration. The data of this study suggested that MMC-CH may have a somewhat more beneficial effect than surgery alone when administered in optimal dose and schedules, but the MMC concentration of the peritoneal fluid was not sufficient to eradicate remnant cancer cells, and effective duration of maintenance was only below 24 hours in the peritoneal fluid and plasma.

Loop와 HPLC Purification 방법보다 더 높은 비방사능을 보여주는 카트리지 Methylation과 Purification을 이용한 손쉬운 [ ¹¹C]PIB 합성

이용석,조용현,이홍재,이윤상,정재민,Lee, Yong-Seok,Cho, Yong-Hyun,Lee, Hong-Jae,Lee, Yun-Sang,Jeong, Jae Min 대한핵의학기술학회 2018 핵의학 기술 Vol.22 No.2

$[^{11}C]PIB$는 베타아밀로이드($A{\beta}\;plague$)라는 변성 단백질에 결합하여 뇌의 기능과 기억력을 서서히 감퇴시키는 비가역적인 질환인 치매를 조기에 감별할 수 있는 대표적인 방사성의약품이다. 지금까지 많은 실험실에서 $[^{11}C]PIB$는 자동화합성장치에서 $[^{11}C]methyl\;iodide$나 $[^{11}C]methyl\;triflate$를 만든 다음 loop나 vial 방법을 사용하여 methylation을 한 다음 HPLC로 정제를 하는 것이다. 하지만 기존의 보고된 방법은 시간이 오래 걸리며, HPLC와 같은 복잡한 시스템을 필요로 하여 소규모 실험실에서 합성하기에 적합하지 않으며, 최종 product에서 에탄올 함량이 높다는 단점이 있었다. 이러한 단점을 보완하기 위하여 카트리지만을 사용하여 카트리지에서 methylation과 purification을 동시에 실시함으로써 합성 시간을 단축하고, 비방사능이 높고, 낮은 에탄올 함량을 가진 $[^{11}C]PIB$를 합성 가능한지 확인하고자 하였다. 가장 널리 사용하는 카트리지 6종(CM, HLB, Alumina, C18, tC18, tC18 environmental을 선택하여 screening test를 실시하였다. 6-OH-BTA-0 1 mg을 c-HXO에 녹인 다음 6개의 카트리지에 loading를 한 다음 0.5 M MSP(pH 5.1) 20 mL로 정제를 한 다음 최종 fraction을 받아서 analytical HPLC로 전구체 잔류량을 측정한 결과 hydrophobicity가 낮은 계열(CM, HLB, Alumina)의 카트리지에서는 완충액으로 정제를 하였을 때 잔류전구체의 양이 많았으나, 탄소함량이 많은 계열의 카트리지(C18, tC18, tC18 environmental)에서는 잔류전구체의 양이 CM, HLB, Alumina 카트리지에 비하여 상대적으로 적었다. 완충액의 정제 농도와 부피를 최적화 하기 위하여 screening test에서 가장 좋은 결과를 나타낸 C18 series cartridge를 가지고 추가 실험을 진행하였다. 인산완충액 농도를 10 mM, 20 mM, 30 mM, 40 mM, 50 mM, 250 mM, 500 mM로 변화시켰으며, 에탄올 함량은 20%와 30%로 하여 용출액을 분석하여서, $[^{11}C]PIB$를 카트리지로 합성하기 위한 최적의 조합은 tC18 environmental cartridge와 0.5 M MSP 20 mL인 것을 알 수 있었다. 기존에 보고된 방법과 cartridge를 비교한 결과, 합성시간에서는 각각 15 ~ 18min, 8 ~ 9 min이 소요되었으며, product activity는 각각 $4.1{\pm}1.4\;GBq$ (n=41), $3.8{\pm}0.9\;GBq$ (n=3), 방사화학적 수율(based on HPLC analysis of the crude product)에서는 $13.9{\pm}4.4%$ (n=41), $12.3{\pm}2.2%$ (n=3)로 별다른 차이가 없었으며, 비방사능에 있어서는 HPLC purification method가 $78.7{\pm}39.7\;GBq/{\mu}mol$ (n=41), cartridge method가 $420.6{\pm}20.4\;GBq/{\mu}mol$ (n=3)로 카트리지 방법이 기존 방법보다 더 좋은 결과를 나타내었다. 또한, 잔류 용매(c-HXO)도 vial or loop method와 별다른 차이가 없었으며, 에탄올 함량에 있어서는 70%(기존 방법)에서 30%(카트리지 방법)로 두 배 이상 함량이 적다는 사실을 알 수 있었다. 지금까지 알아본바와 같이 cartridge method는 reported method(HPLC purification)에 비하여 더 향상된 결과를 보여준다는 사실을 확인하였다. $[^{11}C]PIB$ synthesis has been performed by a loop-methylation and HPLC purification in our lab. However, this method is time-consuming and requires complicated systems. Thus, we developed an on-cartridge method which simplified the synthetic procedure and reduced time greatly by removing HPLC purification step. We compared 6 different cartridges and evaluated the $[^{11}C]PIB$ production yields and specific activities. $[^{11}C]MeOTf$ was synthesized by using TRACERlab FXC Pro and was transferred into the cartridge by blowing with helium gas for 3 min. To remove byproducts and impurities, cartridges were washed out by 20 mL of 30% EtOH in 0.5 M $NaH_2PO_4$ solution (pH 5.1) and 10 mL of distilled water. And then, $[^{11}C]PIB$ was eluted by 5 mL of 30% EtOH in 0.5 M $NaH_2PO_4$ into the collecting vial containing 10 mL saline. Among the 6 cartridges, only tC18 environmental cartridge could remove impurities and byproducts from $[^{11}C]PIB$ completely and showed higher specific activity than traditional HPLC purification method. This method took only 8 ~ 9 min from methylation to formulation. For the tC18 environmental cartridge and conventional HPLC loop methods, the radiochemical yields were $12.3{\pm}2.2%$ and $13.9{\pm}4.4%$, respectively, and the molar activities were $420.6{\pm}20.4GBq/{\mu}mol$ (n=3) and $78.7{\pm}39.7GBq/{\mu}mol$ (n=41), respectively. We successfully developed a facile on-cartridge methylation method for $[^{11}C]PIB$ synthesis which enabled the procedure more simple and rapid, and showed higher molar radio-activity than HPLC purification method.

Controlled post-sulfurization process for higher efficiency nontoxic solution-deposited CuIn_0.7Ga_0.3Se₂ absorber thin films with graded bandgaps

Jang, Jin Woo,Lee, Seung Min,Choi, Ik Jin,Cho, Yong Soo ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.710 No.-

<P><B>Abstract</B></P> <P>A practical way of adjusting post-sulfurization process with variable durations is proposed to improve the cell-conversion efficiency of non-toxic solution driven CuIn<SUB>0.7</SUB>Ga<SUB>0.3</SUB>Se<SUB>2</SUB> absorber thin films. The degree of bandgap grading was controllable by changing the sulfurization time from 2 min to 30 min due to the dissimilar distribution of sulfur across the absorber layer. Deeper intensified distributions of Ga and S were responsible for enhancements in the open-circuit voltage and cell-conversion efficiency. A competitive efficiency of ∼8.81% for the 10 min-sulfurized CIGSSe cell was achieved with other promising parameters, i.e., short-circuit current density of 33.17 mA/cm<SUP>2</SUP>, open-circuit voltage of 0.496 V, and fill factor of 53.5%, resulting from the improved carrier collection and reduced recombination by the bandgap grading. This improved efficiency corresponds to a ∼15.6% enhancement compared to the unsulfurized sample.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Controlled post-sulfurization process enhances cell efficiency of CuIn<SUB>0.7</SUB>Ga<SUB>0.3</SUB>Se<SUB>2</SUB>. </LI> <LI> Sulfur penetrates easily toward the back contact with concentration gradient. </LI> <LI> A graded bandgap structure is responsible for the improved charge collection. </LI> <LI> The achieved cell efficiency of ∼8.81% corresponds to the ∼15.6% enhancement. </LI> <LI> Actual bandgap variations are projected on the basis of elemental distributions. </LI> </UL> </P>